Handguns

Beretta 92FS

The Beretta 92FS appears to be the sidearm carried by the Military Police personnel at Hawkins National Laboratory. The use of the pistol is anachronistic since the M9 pistol was not adopted by the U.S. military until 1985 (and did not enter service widely until 1990), while the show takes place in 1983. It would be more accurate for them to be issued the Colt M1911A1 like the government agents. The majority of these pistols in the series appear to be replicas.

Beretta 92FS - 9x19mm

A Military Police officer holds his Beretta 92FS and a government agent holds his Colt M1911A1 on Chief Jim Hopper in "Chapter Five: The Flea and the Acrobat" (S01E05). Note how these appear to be either dummy or airsoft replicas.

Colt M1911A1

The Colt M1911A1 is carried by government agents including Connie Frazier (Catherine Dyer). Chief Jim Hopper (David Harbour) is issued one when he and Joyce venture into the Upside Down in "Chapter Eight: The Upside Down" (S01E08)

Colt M1911A1 - .45 ACP

Connie Frazier (Catherine Dyer) uses a suppressed M1911A1 to kill Benny the diner owner in "Chapter One: The Vanishing of Will Byers" (S01E01)

The agent on the right holds a M1911A1 in "Chapter Five: The Flea and the Acrobat" (S01E05).

An agent grabs an M1911A1 off a rack at the Hawkins National Laboratory (which, in real life, used to be the Georgia Mental Health Institute) in "Chapter Six: The Monster" (S01E06).

Another agent takes an M1911A1 in "Chapter Six: The Monster" (S01E06).

The M1911A1 holstered on Hopper's belt as he and Joyce search the Upside Down version of the Hawkins Library

Connie Frazier draws a M1911A1 on the boys and Eleven inside the school.

Smith & Wesson Model 10 M&P

Jonathan Byers (Charlie Heaton) takes his father's Smith & Wesson Model 10 when he and Nancy Wheeler (Natalia Dyer) set out to find the monster in Myrkwood in "Chapter Five: The Flea and the Acrobat" (S01E05). She later uses it to fight the Demogorgon in "Chapter Eight: The Upside Down" (S01E08). It also appears to be the weapon used to fake Benny's suicide in "Chapter Two: The Weirdo on Maple Street" (S01E02)

Smith & Wesson Model 10 - .38 Special

Jonathan steals a Model 10 from the glove box of his dad's Oldsmobile 442 after his brother's funeral while Nancy looks on.

Jonathan Byers (Charlie Heaton) practices firing the Model 10 at some beer cans. "I'm trying to hit the space between the cans."

Nancy Wheeler (Natalia Dyer) takes aim at a beer can during shooting practice with Jonathan. Her "golf club-style" grip seems unorthodox, but it's probably safe to assume that most high-school girls don't know how to properly hold a handgun. Despite this, she hits the can on her first shot.

The revolver in Nancy and Jonathan's box of monster hunting supplies in "Chapter Seven: The Bathtub".

Smith & Wesson Model 66

Hopper holds the revolver in "Chapter Five: The Flea and the Acrobat" (S01E05).

Hopper aims his Model 66 at a hazmat suit-wearing agent inside the Hawkins National Laboratory in "Chapter Five: The Flea and the Acrobat" (S01E05).

Submachine Guns

Heckler & Koch MP5K

Heckler & Koch MP5Ks with Navy trigger packs, sometimes fitted with a flashlight, are used by government agents and MPs throughout the series. Jim Hopper uses one in "Chapter Eight: The Upside Down" (S01E06).

Heckler & Koch MP5K with "Navy" trigger pack - 9x19mm

An agent loads an MP5K in "Chapter Two: The Weirdo on Maple Street" as a team prepares to reconnoiter the gate site, giving an excellent view of the attached flashlight.

He then does an "HK Slap", chambering a round.

An agent opens a locker with an MP5K inside it at the Hawkins National Laboratory in "Chapter Six: The Monster" (S01E06).

The agent grabs the MP5K in "Chapter Six: The Monster" (S01E06).

Hopper holds his MP5K in the Upside Down in "Chapter Eight: The Upside Down" (S01E06).

A side view, showing the Navy trigger group.

An agent opens fire with a MP5K as the Demogorgon attacks the school

Heckler & Koch MP5K (Mock MP5K-PDW)

Heckler & Koch MP5Ks with PDW stocks attached are also used by agents. Since the show takes place in 1983, this is considered anachronistic since the MP5K-PDW variant was not developed until 1991. Some of the stocks actually look to be UMP-style stocks, making them even more anachronistic.

Heckler & Koch MP5K with the PDW-style folding stock attached, commonly used in films to emulate the MP5K-PDW - 9x19mm